CA1105664A

CA1105664A - Machine and process for manufacturing flat-bottomed plastic bottles

Info

Publication number: CA1105664A
Application number: CA317,078A
Authority: CA
Inventors: Samuel S. Aidlin; Stephen H. Aidlin
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-11-29
Filing date: 1978-11-29
Publication date: 1981-07-28
Also published as: JPS5630170B2; AU520550B2; AU4200778A; EP0002245A1; EP0002245B1; DE2861035D1; JPS5490275A; US4132584A

Abstract

ABSTRACT OF THE DISCLOSURE
A machine and process for manufacturing plastic bottles by fitting round-bottomed hollow bodies of plastic material to flat-bottomed heels or base cups of similar material comprising a turntable forming a multiplicity of peripherally equispaced seats at a lower level and a like number of outwardly open radial recesses or pockets aligned therewith at an upper level. The hollow bodies are entrained by a conveyor from a blow-molding unit, in which they are produced, on a shelf which enters the turntable generally tangentially between the two levels and continues along a fraction of its periphery to a point just beyond a feeding station at which the separately produced heels are successively deposited on seats pa sing below the shelf. The hollow bodies, introduced by the conveyor into respective pockets above the shelf, then descend onto the underlying heels which are coated with a bonding agent such as a plastic melt. The body and its heel are held in firm contact, over another fractional revolution of the turntable, by a plunger preferably disposed thereabove; the resulting bottles are extracted further downstream by a stationary unloader.

Description

Our present invention relatss to a machins and process for manufacturing plastic bottles for beverages, especially soft drinks, by fitting presh~pao round-bottomed container bodies with complsment-ary flat-bottomed heels or base cups of prsferably the sams resinous mat0rial . ~
Backqround of the Invention `
A known method of manufacturing plastiG bo-ttles of thermo-plastic synthetic resins includes the blow-molding of thin-walled containers from heavier parisons. These containers are generally mads `~
with rounded undersidss since attempts to blow-mold flat-bottomad hollow bodies hava not given satisfactory results in terms of stability against deformationO It has therefore already be~n proposed to assembla such bottles from two complementary m~rnbers~ i~e. a blow-molded body and a separately molded base cupl ~irmly bonded to sach otherO
Object of the_Invsntion The object of our prssent invention is to provide an efficient machine for carrying out this manu~acturing proce~s with relatively simpls means.
Summary o~ the Invention According to the prss~nt invention, plastic bnttles with substantially flat undersides are produced !oy blow-molding a ~eries of hollow plastic container membsrs having round battom surfaoes, separatsly molding a series of ~lat-bottomed base members with concavs upper surfaces which are substantially ~omplementary to the afore-mentioned bottom surfaces, and simultaneously advancing these two ;~
.
series of container and base members over merging paths~in synchronized steps whereby ~ach container me~bar encounters a respective ba~e msmber at the merger pointO The co~plomuntary surfaces of ona series o~
members~ preferably the upwardly facing bass membsrs~ are adhesively

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coated on the approach of ~ach such member to the merger point at which each cnntainer member and respectiv0 base member are interFittsd with their complemen-tary surfaces contacting each other, that contact being maintainsd during furthsr advance of th~ members beyond the mergsr pointa ' ~' A machine for carrying out th~ above process, according to the invention, co-operating with sources of supply for container m0mbsrs and complementary base members to be combinsd into ~inished workpiecss in the form of bottles, comprising a gensrally horizontally moving transportsr provi~ed with s8at5 for the base members and with holders for the container members at a more elevated leuel. A series of pre-shaped container members are carried by first conveyor means to a loading station adjacent the transporter for successive in~rtion into respective holders whil~ a series of base members are concurrsntly ¢~iried by second conveyor moans to a feeding station adjacent the transporter for su=cessive d6position on respective ssats in line with the insertad container members. The two series of camplemsntary .
members may be produced in the same plant by a blow-molding unit and an injection-molding machine~ yet they could slso be prefabricated and 2û brought on from respectiue sterage facilities. A bonding agent, which may be a thermoplastic melt~ i~ sprayed by an applicator on the concave upper surface of the oup-shaped base memb~rs or heels, traveling on ths corresponding conveyor moans toward ~he transportar~ Upon propsr emplacement of a base embsr and a containsr mambsr on ths transporter, with their complsmentary contact ~urfaces confronting each other, a clamping mechanism pres3es them together at thasa contact surfaces during hardening of the bonding`~gsnt. When the latter has substan- ;
tially set, the finished workpieca is removed from tha transporter oy an extractor located at an unloading Qta~io~, e.g~ a statianary daflector. The transports~ and the conveyors ~re preferably drivsn~ -continuously or in steps~ by a common motor alqo synchronized with the

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clamping mschanism.
In a preferred embodimsnt of tlle i~vention~ mare fully des-cribad hereina~ter, the transporter is a turntable with radial pookets con~tituting tha cuntainer holders. The pockets are advantagsously designed as tWD tiers of alignad p~ripheral recesses separated by an annular gap in which vanes of the first convsyor means as w~ll as the unloading dePlector may engag~; a third tier of reces~ss ~orms - -- part of the seats fDr tha base members, holding them in line with ths associatsd container membsrsa To preuent the latter from descsnding prematurely onto the base mamb~rs~ especially when the loading atat1on prscedes the fe~ding station as s~en in the direction of rotation of , . . .
the turntable~ we prs~er to support them on an extsnsion ef their conveyor track hugging a peripheral sactor of thH turntable between the levels of the seats and the pockets~ this support ending just beyond the fseding station at a point whsre the clamping mech~nism becomes effective to hold th~ asse~bl~d bottle compressed until it reaches the unloading st3tion. The sav~ral tiers of recesses are advantagaously formed in respective ~oaxial disks ~orming part o~ the turntable.
Rhe clamping mschan1sm preferably comprisas a sst o~ piungers, one for each pocket~ rotating wi~h th~ turntable and operated by ~luid pressurs through a simple ~olye ~ystem co~trolled by the rotary motion.
This ensures th~t sach pl~ng~r.~ is aqtive over a precisely de~ined tranSpOrt path lying betwsen thq~f~eding and unIoading stations~

The above and other ~e~wres ~ $hZ inuention will now be r ;;` described in detail with r~r~a to t~ aoco~p~nying drawings in whiohs i Flg. l ig a~t6~ nt a bottler~king pl~nt e~bodyiag the -invention;
Fig. 2 i~ an el~eua~io~ol View~o~ ths plan~ illustrated in~

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Fig~ 1, with parts broken away;
Fig. 3 is a cross~sectional view taken on the line III III
o~ Fig~ 1 but drawn to a larg~r scala; and Fig7 4 is a perspective view of part of the plant shown in Flgs, 1 and 2.

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As illustrated in Figs. 1 and 2, a plan-t ~or producing molded soft-drink bottles comprises a conveyur 1 ~or transportiny thermoplastic container bodiss from a blow-molding machine 2 to a 1~ turntable 4~ The turntable includes tllree stacksd circular disks 5~ .;
6, 7 mount~d for ratation about a sha~t 8 which i8 journalsd in a ~rams 50 and driven by a motor l5. The disks S~ 6 7 are provicl~d with ~i~teen peripherally equispaced sets o~ vertically ali(JIled radlal recesses 17a, 17b, 17c, th0 upper and intermediats recesses 17a, 17b forming fiftesn generally semicylindrical outwardly and upwardly open pocksts 17 for the rsc~ption o~ oncoming container bodies 27 carrisd ~rom blow~molding unit 2 by convsyor 1. Each pocket 17 is ouerhung - by a mounting 18 supporting a pnaumatic cylinder 20 providsr.i with a plunger 44O Mounting 18 is intagral with an upright arm 22 9 attached Z to turntable~4 by a pair of brackets 23~ 24, also forming a seat 21 .
framed by the lower recsss 17c. Upright stays 19 ~uxtaposed with each pocket 17 ssrva to maintain the turntable disks 5-7 in v~rtical :r and angular alignment~ . :
. The thin-walled round-bot~med bodies 27 are shaped in ths usll-known manner7 four at a time~ in chamb~rs 9 of blow~molding unit 2 ~uspsnded abovs ~rame 50O Ths four container members produced in each molding cycle are deposit~d on a gsnsrally 5-8hapsd horizontal track - 3 ~ormed by a shelf rigid wlth Frams 5P, caoh containsr msmber being p~aced in a bay 52 de~ined by traok 3 and a pair-o~ van~s lOo In ordsr to advance the moldsd container msmbers 27 along track 3, ths yanes 10 are attached to a cog b~lt 11 partly wound around two .

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rotating sheaves 12 and 1~5; ths larger sheave 12 is toothed for positi~e sngagament with belt 11 and is driv0n by motor 15 via a vertical shaft 14 journaled in Frame 50. The vanes 10 move at a level betwsen the upper and middl~ tiers of recesses 17a, 17b, ent0ring the annular gap betw00n disks 5 and 6 at a loading station 53 to transfer ths oneoming eontainPr bodies to the pockets 17 ~ormed by these recsssss from the bays 52 whoss path at that point ov~rlaps that of the pockets~
The rotation of the turntable by mDtor 15 via a transmission 16 is eontrolled by an array of photoelectric sensors disposed alongsid0 ths path of conveyor 1 in line with molding chambers 9 to monitor -the discharge of successiv0 sets of container bodi~s 27, four at a tirns, from maehine 2. If blow-molding stops, or if less -than four such bodies are procluce~ in a molding cycle (which corrssponds tu a rotation of turn-table ~ through four times the angular pitch o~ pockets 17~ i.e. 96, and an advance of conveyor 1 by as msny bays 52), s0nsors 46 operat~ a controller 64 to de-energizs ths motor 15. For this purpose, the sensors are periodically actiuated by a non-illustrated timer syn-chronized with th~ motor to det~et light rays from radiation emitters across the conveyor 1 if no container bodies are interpos~ci. Controll~r 64 may include a dslay eireuit dssignscl to prevent ths d0activat.ion of motar 15 until the containsr bodies alrssdy mold~d hav~ been fully proc~sse~. A hand-operated switeh 65 may.be ussd to overrids the sensors 46 and to r0start ths eonveyor and turntabls drive with manual inssrtion o~ eontainer bodies-previously molded (or possibly coming ~rom another souree) into aeeassibls bays 520 Ths S~shaped track has an arcuat~ t~rminal ssgment 3~ bound0d on its eonvHx sids by an upstanding guardrail 25 serving to confins the container bodies 27 to their poek0ts 17. Track s~gment 3~ ends in a radially orient0d edge 29S rail 25 cclntinuing beyond that edgs along a periphsral sector 3C of turntabl~ 4 to an unloadin~ station 73 where an extension 25~
thsrsof bends radially away~from the turntabl0 opposite a static1nary . -6-~, guide wall 30 defining thsrewith a discharge ramp 31. Wall ~50 i9 provided with a dcflecting finger 32 projecting between bottom disk 7 ~nd midole disk 6 of the turntable to extract oncominq containe~
bodies from pockets 17. Another segmant 3" o~ track 3, partly ' curued in a sense opposite that of segment 3~, has a vertical web 26 seruing to guide the bodies'27 during their entrainment by conveyor . . _ . .
In Fig. 4 we have shown a feeding station 74 at which substantially flat-bottomed base cups or heels 28, with concave upp~r ~
contact surfaces 67 complementary to the rounded undersidas 66 of '' bodies 27, are successively conveyed from a non-illustrated supply (e.g. an injsction-molding machins synchronized with blow-molding machine 2) to turntable 4 by a ehute 34 provided in its lower reach~ ,~
approaching the turntabls~ with an end],ess belt 35. As a base cup 2~ mDves down this chute~ it passes a laterally retractad upstream barrier 38 and comes to rest against a downstream barrier 37 ~xtendsd across the conveyor path~ tha two barrisrs being linked with rsspect~
ive pneumatic actuators 3a, 41 under the contrul of the afure-mentioned timer~ Ths drivs uf belt 35 includes a non-illustrated transnlission~powared by motor 15 so that this bslt, tuo~ comes to a halt when the motor i9 deactivated by ~he sensors 46.
~arrier 36, whose separation from barrier 37 barely exceeds the diameter of a base cup 28~ interpose& itself between the arrested cup and the following ones to,prevent then~l from pressing against the form~r~ Next7 ths timer actuates 8n applicator 39 puised above the confin2d cup to cuat its upper surface with a liquid bonding agent supplied through a conduit 40~ e.g. a ~elt adhesive. Therea~tsr7 barriar 37 is withdrawn and a blast of air from several nozzles 42, connected to a conduit 47~ propels th~ adhesive-coatad cup forwsrd onto a saat 21 then lo¢ated,at ~seding etation 73. As the turntable ,advances, a container body 27 he1d'in a raised position in the ~7~
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associated pocket 17 by the stationary track extension i~ crosses the sdge 29 and descends into contact with -the cup, ~artly undsr its own weight and partly under pressure of a plunger ~l4 concurrently ackuated by the ouerlyirlg air cylinder 20. Th~ two members 27, 28 remain und~r this air pressure as the adhesive between their contact surfaces hardens on the way to unloading station 73O
For operating the plungPrs 44 upon their arrival above sdgs 29, pressurized air is fad to each cylinder 20 by a respective pair oF
hoses 75, 76 connected at their infeed ends to a value coupling 77 (Figs~ 1 and 2) comprising a rotating lowsr disk 78 on the shaft ~ of turntable 4 and a stationary upper disk 79 provided with tWD arcuat~
slots B~, al which communicate with an air comprsssor (not shown).
Upon ths clearing of edgs 29 by a pockst 17, the associated upper hose 75 conducts pressurized air from the small slot B0 to the uppsr end of the respsctive cylinder 20, thus driving the plungsr 43 down-ward. The plunger remains in this extendsd position until the asscciated pocket 17 reach~s the unloading station 73, whereupon the lower hose 76 is pressurizsd by air from the large slot 81, thus rstracting the plunger.
T~s synchronized drives for conv~yor 1~ turntable 4 and fseder belt 35 mày operate continuously or intermittsntly9 e.gO in skeps corresponding to an advance of ths turntable by one pocket (i.~. ~4 ).
The container bodies 27 may be blow-molded from poly~thylen~
terephthala-te, for ~xample9 which is impervious to gases and can thsre~ore be used with carbonatad bsverages. The base cups 28, on ths other hand, may con~ist simply o~ polyethylen~.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A machine for producing plastic bottles with substantially flat undersides by bonding round-bottomed preshaped hollow plastic container members to complementary substantially flat-bottomed base members, comprising:
a generally horizontally moving transporter provided with seats for said base members and with holders For said container members above said seats;
first conveyor means extending from a supply of said container members to a loading station adjacent said transporter for successively inserting a series of container members into respective holders thereof;
second conveyor means extending from a supply of said bass members to a feeding station adjacent said transporter for successively depositing a series of base members on respective seats thereof in line with the inserted container members, with a lower contract surface of each container member confronting a complementary upper contact surface of the aligned bass member;
applicator means coacting with one of said conveyor means for coating one of said contact surfaces with a bonding agent preparatorily to emplacement of each member of the corresponding series on said transporter;
clamping means on said transporter operable upon emplacement of aligned container and base members for pressing them together at said contact surfaces thereof during hardening of said bonding agent to produce a finished workpiece;
extraction means at an unloading station downstream of said loading and feeding stations for removing successive workpieces from said transporter; and drive means for synchronously operating said transporter, said first and second conveyor means and said clamping means.

2. A machine as defined in claim 1 wherein said transporter comprises a turntable with peripherally equispaced outwardly open radial pockets constituting said holders, said first conveyor means forming a track approaching said turntable generally tangentially for radially introducing said container members into said pockets, said pockets being disposed at a level above that of said seats.

3. A machine as defined in claim 2, wherein said loading station precedes said feeding station in the direction of rotation of said turntable, further comprising support means for maintaining said container members spaced above said seats in said pockets between said loading and feeding stations.

4. A machine as defined in claim 3, wherein said support means comprises an extension of said track embracing a peripheral sector of said turntable between the levels of said pockets and said seats.

5. A machine as defined in claim 4 wherein said turntable comprises a plurality of vertically spaced coaxial disks with aligned peripheral recesses including a lower disk, an intermediate disk and an upper disk, the recesses of said intermediate and upper disks cons-tituting said pockets, the recesses of said lower disk forming part of said seats.

6. A machine as defined in claim 5 wherein first conveyor means includes a set of vanes for entraining said container members on said track, said vanes being displaceable on a level between said inter-mediate and upper disks into an annular gap between said disks for inserting the strained container member into said pockets.

7. A machine as defined in claim 6 wherein said extraction means comprises a stationary deflector reaching into said gap down-stream of said feeding station.

8. A machine as defined in claim 3 wherein said pockets are accessible from above, said clamping means comprising a set of plungers above said pockets and actuating means for lowering each plunger onto a container member in the underlying pocket upon movement thereof past said feeding station, said support means being a stationary shelf terminating at said feeding station.

9. A machine as defined in claim 8 wherein said second conveyor means includes an endless belt, further comprising retractable gate means synchronized with said drive means for arresting an oncoming base member immediately ahead of said feeding station in line with said applicator means to enable the coating thereof with said bonding agent.

10. A machine as defined in claim 9 wherein said second con-veyor means further includes nozzle means for generating an air jet upon retraction of said gate means to drive the coated bass member onto a confronting seat of said turntable.

11. A machine as defined in claim 9 wherein said gate means comprises a pair of barriers upstream and downstream of said applicator means, the upstream barrier being interposable between a base member being coated and further bass members entrained by said belt.

12. A machine as defined in claim 1 wherein the supply of container members includes a blow-molding unit producing a predeter-mined number of container members at a time, said first conveyor means being positioned to receive said number of container members, further comprising monitoring means at said blow-molding unit for deactivating said drive means upon failure of said first conveyor means to receive said number of container members at regular inter-vels.

13. A process for producing plastic bottles with substantially flat undersides, comprising the steps of;
blow-molding a series of hollow plastic container members having round bottom surfaces;
separately molding a series of flat-bottomed bass members with concave upper surfaces substantially complementary to said bottom surfaces;
advancing said series of container members stepwise over an assigned path past a merger point while directing said series of base members toward 5 location close to said merger point;
briefly arresting each base member at said location;
adhesively coating each arrested base member at said location;
propelling each coated base member with the aid of a jet of air to said merger point in timed relationship with the advance of said container members;
interfitting each container member and a respective base member, meeting at said merger point, with their complementary surfaces contacting each other and maintaining said contact during further advance of said members beyond said merger point.

14. A process as defined in claim 13, wherein said base members are propelled toward said merger point substantially perpendicular to said path.

15. A process as defined in claim 13, wherein said container members are blow-molded from polyethylene terephthalets.

16. A process as defined in claim 13, wherein said base members are molded from polyethylene.